Disclosed is a three-dimensional object shaping apparatus for forming an object with a desired shape in a three-dimensional space represented by a three-dimensional orthogonal coordinate system of xyz. The three-dimensional object shaping apparatus includes a light source; a drive mechanism to move the shaping surface parallel to an xy plane in a z axis direction; an optical scanning unit to scan light emitted from the light source along a y axis direction perpendicular to the z axis; and a rotation mechanism to rotate one of the optical scanning unit and the shaping surface relative to each other with respect to the z axis as a rotation axis, where a pattern of the light to be applied to the shaping surface is controlled by a combination of a rotation of the shaping surface performed by the rotation mechanism and the scanning of the light performed by the optical scanning unit.
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1. A three-dimensional object shaping apparatus for forming an object with a desired shape by application of light onto a shaping surface or a material disposed on an already shaped layer on the shaping surface in a three-dimensional space, the three-dimensional space being represented by a three-dimensional orthogonal xyz coordinate system, and the three-dimensional object shaping apparatus comprising:
a light source configured to emit light;
a driver to move the shaping surface or the material, which are parallel to an xy plane of the xyz coordinate system, in a z axis direction of the xyz coordinate system;
a polygon mirror configured to scan light emitted from the light source along a y axis direction of the xyz coordinate system, wherein the y axis direction is perpendicular to the z axis, and wherein the polygon mirror rotates about an x axis of the xyz coordinate system; and
a rotator to perform rotation selectable from one or both of the polygon mirror and the shaping surface relative to each other about the z axis as a rotation axis, wherein a pattern of the light to be applied to the shaping surface or the material is controlled by a combination of a rotation by the rotator and the scanning of the light performed by the polygon mirror, and wherein the scanned light travels radially from the rotation axis by scanning the light along a radial direction defined in the xy plane.
2. The three-dimensional object shaping apparatus according to
3. The three-dimensional object shaping apparatus according to
4. The three-dimensional object shaping apparatus according to
5. The three-dimensional object shaping apparatus according to
6. The three-dimensional object shaping apparatus according to
a surface height adjuster for maintaining a surface of the material at a constant height.
7. The three-dimensional object shaping apparatus according to
8. The three-dimensional object shaping apparatus according to
an optical condenser for condensing the light emitted from the light source, wherein a focal surface of the optical condenser is set inward from a surface of the material.
9. The three-dimensional object shaping apparatus according to
10. The three-dimensional object shaping apparatus according to
11. The three-dimensional object shaping apparatus according to
12. The three-dimensional object shaping apparatus according to
13. The three-dimensional object shaping apparatus according to
14. A three-dimensional object shaping method using the three-dimensional object shaping apparatus according to
scanning, by the polygon mirror, light on the shaping surface or the material along the y axis direction;
rotating the polygon mirror about the x axis of the xyz coordinate system;
rotating, by the rotator, at least one of the polygon mirror and the shaping surface relative to each other about the z axis as a rotation axis; and
moving, by the driver, the shaping surface or the material in the z axis direction, wherein a pattern of the light being applied to the shaping surface or the material is controlled by a combination of the rotating and the scanning of the light, and wherein the scanned light travels radially from the rotation axis by scanning the light along the radial direction.
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The present application is based on and claims priority to Japanese Patent Application No. 2018-138631, filed on Jul. 24, 2018, and Japanese Patent Application No. 2018-237473, filed on Dec. 19, 2018, the contents of which are incorporated herein by reference in their entirety.
The disclosures discussed herein relate to a three-dimensional object shaping apparatus and a method for shaping a three-dimensional object.
Three-dimensional object shaping methods (e.g., selective laser sintering and stereolithography) are known to cure a material (such as a thermoplastic resin, a metal, a photo-curable resin, etc.) by irradiation with light to deposit the cured material on a layer-by-layer basis to gradually form a three-dimensional object. Such three-dimensional object shaping methods typically employ the additive manufacturing technology. The additive manufacturing technology includes generating shape data of multiple layers from a shape of an object, and depositing multiple layers based on the generated shape data. In such a related art of additive manufacturing technology, since a three-dimensional shaping is performed by depositing layers based on two-dimensional shape data, the shaping process requires a procedure of initially performing two-dimensional laser scanning on a shaping surface, and subsequently moving the shaping surface together with a stage so as to form a next layer.
Since the two-dimensional laser scanning method typically uses galvano scanning or the like, which requires repeatedly accelerating or decelerating mirror surfaces, there is potential for improvement in terms of scanning speeds.
[Patent Document 1] Japanese Patent No. 4790264
[Patent Document 2] Japanese Patent No. 5570330
The present invention is made in light of the above-described point, and is intended to provide a technology to achieve both high accuracy and high speed shaping of three-dimensional objects.
According to an aspect of an embodiment, a three-dimensional object shaping apparatus is provided for forming an object with a desired shape by application of light onto a shaping surface or a material disposed on an already shaped layer in a three-dimensional space, the three-dimensional space being represented by a three-dimensional orthogonal coordinate system of XYZ. The three-dimensional object shaping apparatus includes
a light source configured to emit light;
a drive mechanism configured to move the shaping surface parallel to an XY plane in a Z axis direction;
an optical scanning unit configured to scan light emitted from the light source along a Y axis direction perpendicular to the Z axis; and
a rotation mechanism configured to rotate at least one of the optical scanning unit and the shaping surface relative to each other with respect to the Z axis as a rotation axis, wherein a pattern of the light to be applied to the shaping surface is controlled by a combination of a rotation of the shaping surface performed by the rotation mechanism and the scanning of the light performed by the optical scanning unit.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.
The following illustrates preferred embodiments with reference the accompanying drawings.
The shaping apparatus 100 of the present invention is a three-dimensional object shaping apparatus. The shaping apparatus 100 includes an optical emitter 20 as a light source, and is configured to form an object with a desired shape by irradiating a material 101 disposed on a shaping surface S with light L emitted from the optical emitter 20. The shaping apparatus 100 includes a collimator lens 21 configured to convert light emitted from the optical emitter 20 into parallel light, a rotation mirror 22 that is a polygonal mirror configured to rotate around a central axis parallel to an X direction, and a scanning lens 23 that is a condensing optical system. The shaping apparatus 100 includes a shaping stage 11 having a surface facing a +Z direction (hereinafter referred to as “+Z direction facing surface”), where a material 101 is disposed to form a finally obtained object P, and a rotation stage 10 acting as a rotation mechanism disposed in a direction toward the −Z axis direction relative to the shaping stage 11 and configured to rotatably support the shaping surface S with respect to a Z axis as the center. The shaping apparatus 100 includes a Z stage 12 configured to support the rotation stage 10 with raising or lowering in the Z axis direction, or more specifically, configured to support the rotation stage 10 movably in ±Z directions, and a shaping tank 102 configured to hold the material 101 around the shaping stage 11. In this embodiment, the Z stage 12 is disposed to penetrate a bottom surface 103 of the shaping tank 102.
The optical emitter 20 may be made of a CW laser, a pulsed laser, or the like, and a short pulse emitting laser with pulse widths of several tens of ps or less is particularly suitable for multiphoton photopolymerization. The collimator lens 21 is a lens that converts light L emitted from the optical emitter 20 into light approximately parallel to an optical axis. The rotation mirror 22 is a rotating polygon mirror having a mirror plane formed on each of side surfaces of a polygonal column (especially a hexagonal column in
In this embodiment, the rotation mirror 22 and the scanning lens 23 are used for scanning beams. However, the configuration is not limited to such an example, and the scanning lens 23 may be a condensing optical system or a reflecting optical system that includes a plurality of lenses addition, the rotation mirror 22 may be an element or a unit for forming one-dimensional scanning light; for example, a galvano mirror or a MEMS mirror may be used. However, the rotation mirror 22 is preferred because acceleration or deceleration of the mirror is required; additionally a reciprocating scanning may cause non-uniformity in a thermal distribution due to the sequence of optically scanning the object not being in a single direction.
The material 101 is, for example, ultraviolet curable liquid resin in the present embodiment, and while the material 101 at irradiation positions Q is irradiated with the scanning light L, the material 101 at irradiation positions Q is cured to gradually form an object P as a three-dimensional object. The material 101 may be any material in which the positions irradiated with the scanning light L form a three-dimensional shape, such as a thermoplastic resin, gel-like material, or the like.
The rotation stage 10 is a cylindrical stage that rotates around a center of the Z axis, and the shaping stage 11 is disposed on the rotation stage 10 in the +Z direction. A material 101 is disposed on the shaping stage 11, and scanning light. L is adjusted so that irradiation positions Q are located on the +Z direction facing surface of the shaping stage 11, as illustrated in
As illustrated with a shaded pattern in
The rotation stage 10 constantly rotates at a predetermined angular velocity during shaping, and one rotation corresponds to shaping of one layer. When the rotation stage 10 rotates once, the Z stage 12 descends in the −Z direction by the thickness of one layer of the shaped object P, that is, by 50 μm in this embodiment. Note that the ratio of one rotation of the rotation stags 10 to a moving speed of the Z stage 12 can be optionally changed. The stage 12 may be moved by the thickness of one layer when the rotation stage 10 is rotated once from an initial position, i.e., when shaping of one layer is completed. However, if the Z stage 12 moves in such a step-wise manner, unnecessary level differences may be formed in the shaped object P. Thus, it is desirable that the Z stage 12 constantly moves at a constant speed. The rotation of the rotation stage 10 is a “rotation step of rotating the shaping surface S with respect to a Z axis as a rotation axis”. Note that the rotation step is not specified as the rotation of the rotation stage 10 alone. The rotation step may be applied to the rotation mirror 22, and may be applied to the rotation stage 10 and the rotation mirror 22 rotating in opposite directions. That is, the rotation step may be applied to any rotations in which the shaping surface S and the optical scanning unit are rotated relative to each other with respect to the Z axis as a rotation axis.
The number of scanning times of scanning light L during one rotation of the rotation stage 10 may be determined in accordance with a desired resolution of the shaped object P and the like; the number of scanning times of scanning light L during one rotation of the rotation stage 10 may be controlled by a desired value, which is determined in accordance with the rotation speed of the rotation mirror 22 and the rotation speed of the rotation stage 10. Note that main scanning in a typical copier may be determined to be movement of the scanning light L in one direction (the Y direction in this case) caused by the rotation of the rotation mirror 22, and sub scanning in the copier may be determined to be a change in the scanning position due to the rotation of the rotation stage 10, according to a conceptual image of a process of forming a shaped object P on the shaping surface S.
As illustrated in
In such shaped patterns, uniform energy may be applied to the material 101 by controlling a typical light source irradiation density as uniformly as possible, thereby obtaining a good shaping result. Accordingly, in the present embodiment, irradiation time intervals are varied between irradiation positions far from the center of rotation and at irradiation positions close to the center of rotation such that the irradiation density per area is controlled to be uniform. Alternatively, the irradiation density per area may be controlled by adjusting lighting intervals of the optical emitter 20.
In
As already described above, a rotation of the rotation stage 10 corresponds to 50 μm, which is a thickness of one layer obtained by one rotation, in the present embodiment. Thus, when the rotation stage 10 rotates 360 degrees, the Z stage 12 descends toward the −Z direction by one layer, i.e., 50 μm (driving step). By such descent, the material 101, which is filled in the shaping tank 102, spreads over the shaping surface S, thereby supplying the material 101 to the shaping surface S.
Note that the configuration of the supply of the material 101 is not limited to the above-described configuration of spontaneously spreading of the material 101 by the descent of the Z stage 12; the configuration of the supply of the material 101 may be implemented by a surface height adjusting unit 15 for maintaining a surface of the material 101 at a constant height, as illustrated, for example, in
This point is described below in further detail.
Thus, according to the embodiment of the present invention, while the main scanning is performed by rotation of the rotation mirror 22, the shaping surface S is moved in a direction corresponding to the sub-scanning direction by rotation of the rotation stage 10 and moving of the Z axis of the Z stage 12. As a result, the throughput will be improved by not causing disproportion a thermal distribution and not causing interruption or acceleration/deceleration. Such a configuration enables both high accuracy and high speed in shaping of three-dimensional objects. In other words, the shaping apparatus 100 according to the present embodiment includes a Z stage 12 configured to move the shaping surface S in a Z axis direction; a rotation stage 10 configured to rotate at least one of an optical scanning module 25 and the shaping surface S relative to each other with respect to the Z axis as a rotation axis, and an optical scanning unit configured to scan scanning light L along a Y axis direction perpendicular to the Z axis, such that patterns of the scanning light L applied to the shaping surface S are controlled by a combination of a rotation of the shaping surface S performed by the rotation stage 10 and the scanning of scanning light L performed by the optical scanning unit. Such a configuration enables both high accuracy and high speed in shaping of three-dimensional objects.
The scan line B1 illustrated in
In the following, a second embodiment of the present invention will be described. A shaping apparatus 200 illustrated in
In the second embodiment, a shaping surface S is disposed on a −Z direction facing surface of the rotation stage 10 with the shaping surface S disposed thereon facing toward a −Z direction. Accordingly, it a gap is formed between the shaping tank 102 and the shaping surface S, the gap is automatically filled with the material 101 with a uniform thickness for curing the material 101 with the scanning light L. Further, the bottom surface 103 is made of a transparent material to allow the scanning light L to pass through.
In general, in a shaping apparatus having such a suspending type configuration where the scanning light L is emitted from the −Z toward the direction (from lower to upper direction), the material 101, especially, the liquid material 101, is automatically formed with a uniform thickness within the gap, which would provide an advantageous effect in the improvement of the shaping accuracy.
Further, in such a suspending type shaping apparatus, the bottom surface 103 of the shaping tank 102 and the shaped object P are adhered to each other, so that a step of peeling off of the shaped object P from the bottom surface 103 of the shaping tank 102 would be generally required. However, according to the second embodiment, the angular momentum of the rotation stage 10 acts as a shear force between the shaped object P and the bottom surface 103 of the shaping tank 102. Thus, the bottom surface 103 of the shaping tank 102 is separated from the shaped object P by rotation of the rotation stage 10 without requiring a peeling-off step.
Next, a third embodiment of the present invention will be described. In a typical photofabrication, when the material 101 absorbs scanning light L, energy of light is propagated as heat to the material 101, which changes and cures the material 101. This indicates that it is preferable that a wavelength of light absorbed by the material 101 and a wavelength of the scanning light L be close to each other. In addition, it is also known that the longer the wavelength of light, the longer the transmittance distance of light. However, as illustrated in
Use of such a phenomenon not only cures the surface of the material 101, but also cures a portion near the focal point located by a predetermined distance inward from the surface of the material 101 (material surface). This enables the scanning light L to pass through the material 101 other than the cured portions, thereby improving the shaping accuracy. In addition, in multiphoton polymerization compared to single photon polymerization, although the shaping resolution is improved, the area of the irradiation positions Q would be reduced, which would result in a decrease in the shaping speed. However, according to the configuration of the present embodiment, while the resolution is improved, the speed of shaping is increased; thus, more suitable shaping of a three-dimensional object may be achieved by the multiphoton polymerization.
Further, since a gap is provided between the shaping surface S and the bottom surface 103 of the shaping tank 102, the shaped object P will not be adhered to the bottom surface of the shaping tank 102. Thus, a peeling-off step is no longer required, thereby increasing the shaping speed of a three-dimensional object.
Next, a fourth embodiment of the present invention will be described.
The shaping apparatus 200 includes an optical emitter 20, two rotation mirrors 22a and 22b, and scanning lenses 23a and 23b. In the shaping apparatus 200, light from the optical emitter 20 is split into two using a half mirror 16 to direct light toward different regions on the shaping surface 5, where first split light is directed to a rotation mirror 22a and a scanning lens 23a, and second split light is directed to a rotation mirror 22b and a scanning lens 23b. That is, in this embodiment, a plurality of scanning light rays La and Lb are applied to different positions on a surface of the material 101. In
Alternatively, the shaping apparatus 200 may include optical emitters 20a and 20b, which are independent of each other, as illustrated in
Next, a fifth embodiment of the present invention will be described. In this embodiment, as illustrated in
Next, a sixth embodiment of the present invention will be described. In this embodiment, the shaping apparatus 200 includes an optical emitter 20 functioning as a light source, a collimator lens 21, an optical scanning module 25 rotatable around a central axis parallel to the Z direction, a mirror 24a and a mirror 24b forming an optical path by reflecting light guided from the optical emitter 20. The shaping apparatus 200 further includes a rotation member 26 attached to the optical scanning module 25, a rotation mirror 22, and a scanning lens 23. Among the above-described elements, description of the same elements as the first to fifth embodiments will be omitted with reference to the same reference numbers. In the shaping apparatus 200, the optical scanning module 25 rotates with respect to a Z axis as the center, instead of the shaping stage 11, as illustrated in
Use of the sixth embodiment makes it possible to increase the shaping speed, even when the material 101 to be shaped is a liquid material. This feature is described below in detail. In the configurations in the first to fifth embodiments, the shaping surface S is supposed to rotate, as already described above. In such a case, if the material 101 used is a liquid material, rotations of the shaping stage 11 may cause inertial effects in the liquid material 101 such that the shaped object P may flow in an opposite direction to the rotation direction of the shaping stage 11. For example, it is known in the art that when photocuring a liquid material, such as an ultraviolet curable resin, the curing time required for photocuring a liquid material is in the order of milliseconds. When the rotation speed of the rotation mirror 22 is assumed to be a typical rotation speed of 1,000 to 10,000 rpm disclosed in the literature, rendering intervals of a straight line rendered by this method with respect to a rotation direction of the rotation mirror 22 would be 5 to 50 ms, which is on the order of the photocuring time. Accordingly, in the configurations of the first to fifth embodiments, where the rotation stage 10 and the shaping stage 11 are rotated together with the material 101, the material 101 may flow and potentially not form a desired shape in shaping of photo-curable resin.
In this respect, in the method and the configuration used in the sixth embodiment, such an inertial force does not act on the liquid material 101 subject to shaping. Thus, even when the shaping is performed at high speeds, stable shaping will be provided without degrading the accuracy of shaping.
In the sixth embodiment, as a mechanism for rotating the optical scanning module 25, a method of connecting the optical scanning module 25 to a large motor, or a method of performing internally driven rotation of the optical scanning module 25 at any one of surfaces in contact with the optical scanning module 25 may be considered.
As the method of connecting the optical scanning module 25 to a large motor, for example, the rotation member 26 in
The internally driven rotation method, for example, is illustrated in
A shaping apparatus 200 according to the seventh embodiment includes an optical emitter 20 functioning as a light source, a collimator lens 21, an optical scanning module 25 rotatable around a central axis parallel to the Z direction, and a mirror 24 configured to reflect light guided from the optical emitter 20 to form an optical path. The shaping apparatus 200 further includes a rotation mirror 22, a scanning lens 23, a shaping tank housing 104, and a rotation drive unit 27 disposed between the shaping tank housing 104 and the optical scanning module 25. In the above-described elements, the same elements as the first to fifth embodiments will be omitted with reference to the same reference numbers. In the shaping apparatus 200, light guided from the optical emitter 20 is reflected by the mirror 24 and the reflected light is guided to the rotation mirror 22. The optical scanning module 25 is coupled to a rotation drive unit 27, and the rotation drive unit 27 is driven along the shaping tank housing 104 to rotate the optical scanning module 25. Such a rotation drive unit 27 may be rotated by a rotation drive force such as a roller or a rotary device, or the rotation drive unit 27 may be rotated by a rotation drive force from a separate drive unit using a belt or the like. As described above, in this embodiment, the rotation drive unit 27 rotates the optical scanning module 25 including the rotation mirror 22 with respect to the Z axis as a rotation axis to function as a “rotation mechanism that rotates at least one of the optical scanning unit and the shaping surface relative to each other with respect to the Z axis as a rotation axis”. Further, in this embodiment, a step of operating the rotation drive unit 27 to rotate the optical scanning module 25 relative to the shaping surface S corresponds to the rotation step.
According to the shaping apparatus of the above-described embodiments, the shaping accuracy and shaping speed for shaping a three-dimensional object will be simultaneously improved.
Although the preferred embodiments have been described in detail, preferred embodiments are not limited to the above-described embodiments, and various modifications and substitutions may be made to the above-described embodiments without departing from the scope set forth in the claims. For example, respective configurations illustrated as the first to seventh embodiments may be used in combination.
The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention.
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